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IP subnet calculator

Type an address with its prefix or mask to see the network, its usable range and masks. Split it into smaller subnets, or look up any prefix in the reference tables.

Network178.4.64.0/19
Usable hosts8,190
Subnet mask255.255.224.0
Addresses8,192
Network address
178.4.64.0
Broadcast address
178.4.95.255
First usable
178.4.64.1
Last usable
178.4.95.254
Usable hosts
8,190 (8,192 less the network and broadcast addresses)
Subnet mask
255.255.224.0
Wildcard mask
0.0.31.255 (Cisco ACLs, OSPF)
Prefix length
/19
Type
Public public
Old class
B (default /16)
As numbers
Hex B2044000 · Integer 2986622976 to 2986631167
Reverse DNS zones
64.4.178.in-addr.arpa
65.4.178.in-addr.arpa
66.4.178.in-addr.arpa
67.4.178.in-addr.arpa
68.4.178.in-addr.arpa
69.4.178.in-addr.arpa
70.4.178.in-addr.arpa
71.4.178.in-addr.arpa
72.4.178.in-addr.arpa
73.4.178.in-addr.arpa
74.4.178.in-addr.arpa
75.4.178.in-addr.arpa
76.4.178.in-addr.arpa
77.4.178.in-addr.arpa
78.4.178.in-addr.arpa
79.4.178.in-addr.arpa
and 16 more
/19 is not on a 8-bit boundary, so it takes 32 /24 zones.
Binary
Binary view
Binary (network bits bold, host bits grey)Dotted
Address10110010.00000100.01000000.00000000178.4.64.0
Subnet mask11111111.11111111.11100000.00000000255.255.224.0
Network10110010.00000100.01000000.00000000178.4.64.0
Broadcast10110010.00000100.01011111.11111111178.4.95.255
Split into smaller subnets/29
/20 (2)/21 (4)/22 (8)/23 (16)/24 (32)/25 (64)/26 (128)/27 (256)/28 (512)/29 (1,024)/30 (2,048)/31 (4,096)

178.4.64.0/19 makes 1,024 subnets of /29; the first 256 are listed.

Subnets
#SubnetUsable hosts rangeBroadcastHosts
1178.4.64.0/29178.4.64.1 to 178.4.64.6178.4.64.76
2178.4.64.8/29178.4.64.9 to 178.4.64.14178.4.64.156
3178.4.64.16/29178.4.64.17 to 178.4.64.22178.4.64.236
4178.4.64.24/29178.4.64.25 to 178.4.64.30178.4.64.316
5178.4.64.32/29178.4.64.33 to 178.4.64.38178.4.64.396
6178.4.64.40/29178.4.64.41 to 178.4.64.46178.4.64.476
7178.4.64.48/29178.4.64.49 to 178.4.64.54178.4.64.556
8178.4.64.56/29178.4.64.57 to 178.4.64.62178.4.64.636
9178.4.64.64/29178.4.64.65 to 178.4.64.70178.4.64.716
10178.4.64.72/29178.4.64.73 to 178.4.64.78178.4.64.796
11178.4.64.80/29178.4.64.81 to 178.4.64.86178.4.64.876
12178.4.64.88/29178.4.64.89 to 178.4.64.94178.4.64.956
13178.4.64.96/29178.4.64.97 to 178.4.64.102178.4.64.1036
14178.4.64.104/29178.4.64.105 to 178.4.64.110178.4.64.1116
15178.4.64.112/29178.4.64.113 to 178.4.64.118178.4.64.1196
16178.4.64.120/29178.4.64.121 to 178.4.64.126178.4.64.1276
17178.4.64.128/29178.4.64.129 to 178.4.64.134178.4.64.1356
18178.4.64.136/29178.4.64.137 to 178.4.64.142178.4.64.1436
19178.4.64.144/29178.4.64.145 to 178.4.64.150178.4.64.1516
20178.4.64.152/29178.4.64.153 to 178.4.64.158178.4.64.1596
21178.4.64.160/29178.4.64.161 to 178.4.64.166178.4.64.1676
22178.4.64.168/29178.4.64.169 to 178.4.64.174178.4.64.1756
23178.4.64.176/29178.4.64.177 to 178.4.64.182178.4.64.1836
24178.4.64.184/29178.4.64.185 to 178.4.64.190178.4.64.1916
25178.4.64.192/29178.4.64.193 to 178.4.64.198178.4.64.1996
26178.4.64.200/29178.4.64.201 to 178.4.64.206178.4.64.2076
27178.4.64.208/29178.4.64.209 to 178.4.64.214178.4.64.2156
28178.4.64.216/29178.4.64.217 to 178.4.64.222178.4.64.2236
29178.4.64.224/29178.4.64.225 to 178.4.64.230178.4.64.2316
30178.4.64.232/29178.4.64.233 to 178.4.64.238178.4.64.2396
31178.4.64.240/29178.4.64.241 to 178.4.64.246178.4.64.2476
32178.4.64.248/29178.4.64.249 to 178.4.64.254178.4.64.2556
33178.4.65.0/29178.4.65.1 to 178.4.65.6178.4.65.76
34178.4.65.8/29178.4.65.9 to 178.4.65.14178.4.65.156
35178.4.65.16/29178.4.65.17 to 178.4.65.22178.4.65.236
36178.4.65.24/29178.4.65.25 to 178.4.65.30178.4.65.316
37178.4.65.32/29178.4.65.33 to 178.4.65.38178.4.65.396
38178.4.65.40/29178.4.65.41 to 178.4.65.46178.4.65.476
39178.4.65.48/29178.4.65.49 to 178.4.65.54178.4.65.556
40178.4.65.56/29178.4.65.57 to 178.4.65.62178.4.65.636
41178.4.65.64/29178.4.65.65 to 178.4.65.70178.4.65.716
42178.4.65.72/29178.4.65.73 to 178.4.65.78178.4.65.796
43178.4.65.80/29178.4.65.81 to 178.4.65.86178.4.65.876
44178.4.65.88/29178.4.65.89 to 178.4.65.94178.4.65.956
45178.4.65.96/29178.4.65.97 to 178.4.65.102178.4.65.1036
46178.4.65.104/29178.4.65.105 to 178.4.65.110178.4.65.1116
47178.4.65.112/29178.4.65.113 to 178.4.65.118178.4.65.1196
48178.4.65.120/29178.4.65.121 to 178.4.65.126178.4.65.1276
49178.4.65.128/29178.4.65.129 to 178.4.65.134178.4.65.1356
50178.4.65.136/29178.4.65.137 to 178.4.65.142178.4.65.1436
51178.4.65.144/29178.4.65.145 to 178.4.65.150178.4.65.1516
52178.4.65.152/29178.4.65.153 to 178.4.65.158178.4.65.1596
53178.4.65.160/29178.4.65.161 to 178.4.65.166178.4.65.1676
54178.4.65.168/29178.4.65.169 to 178.4.65.174178.4.65.1756
55178.4.65.176/29178.4.65.177 to 178.4.65.182178.4.65.1836
56178.4.65.184/29178.4.65.185 to 178.4.65.190178.4.65.1916
57178.4.65.192/29178.4.65.193 to 178.4.65.198178.4.65.1996
58178.4.65.200/29178.4.65.201 to 178.4.65.206178.4.65.2076
59178.4.65.208/29178.4.65.209 to 178.4.65.214178.4.65.2156
60178.4.65.216/29178.4.65.217 to 178.4.65.222178.4.65.2236
61178.4.65.224/29178.4.65.225 to 178.4.65.230178.4.65.2316
62178.4.65.232/29178.4.65.233 to 178.4.65.238178.4.65.2396
63178.4.65.240/29178.4.65.241 to 178.4.65.246178.4.65.2476
64178.4.65.248/29178.4.65.249 to 178.4.65.254178.4.65.2556
65178.4.66.0/29178.4.66.1 to 178.4.66.6178.4.66.76
66178.4.66.8/29178.4.66.9 to 178.4.66.14178.4.66.156
67178.4.66.16/29178.4.66.17 to 178.4.66.22178.4.66.236
68178.4.66.24/29178.4.66.25 to 178.4.66.30178.4.66.316
69178.4.66.32/29178.4.66.33 to 178.4.66.38178.4.66.396
70178.4.66.40/29178.4.66.41 to 178.4.66.46178.4.66.476
71178.4.66.48/29178.4.66.49 to 178.4.66.54178.4.66.556
72178.4.66.56/29178.4.66.57 to 178.4.66.62178.4.66.636
73178.4.66.64/29178.4.66.65 to 178.4.66.70178.4.66.716
74178.4.66.72/29178.4.66.73 to 178.4.66.78178.4.66.796
75178.4.66.80/29178.4.66.81 to 178.4.66.86178.4.66.876
76178.4.66.88/29178.4.66.89 to 178.4.66.94178.4.66.956
77178.4.66.96/29178.4.66.97 to 178.4.66.102178.4.66.1036
78178.4.66.104/29178.4.66.105 to 178.4.66.110178.4.66.1116
79178.4.66.112/29178.4.66.113 to 178.4.66.118178.4.66.1196
80178.4.66.120/29178.4.66.121 to 178.4.66.126178.4.66.1276
81178.4.66.128/29178.4.66.129 to 178.4.66.134178.4.66.1356
82178.4.66.136/29178.4.66.137 to 178.4.66.142178.4.66.1436
83178.4.66.144/29178.4.66.145 to 178.4.66.150178.4.66.1516
84178.4.66.152/29178.4.66.153 to 178.4.66.158178.4.66.1596
85178.4.66.160/29178.4.66.161 to 178.4.66.166178.4.66.1676
86178.4.66.168/29178.4.66.169 to 178.4.66.174178.4.66.1756
87178.4.66.176/29178.4.66.177 to 178.4.66.182178.4.66.1836
88178.4.66.184/29178.4.66.185 to 178.4.66.190178.4.66.1916
89178.4.66.192/29178.4.66.193 to 178.4.66.198178.4.66.1996
90178.4.66.200/29178.4.66.201 to 178.4.66.206178.4.66.2076
91178.4.66.208/29178.4.66.209 to 178.4.66.214178.4.66.2156
92178.4.66.216/29178.4.66.217 to 178.4.66.222178.4.66.2236
93178.4.66.224/29178.4.66.225 to 178.4.66.230178.4.66.2316
94178.4.66.232/29178.4.66.233 to 178.4.66.238178.4.66.2396
95178.4.66.240/29178.4.66.241 to 178.4.66.246178.4.66.2476
96178.4.66.248/29178.4.66.249 to 178.4.66.254178.4.66.2556
97178.4.67.0/29178.4.67.1 to 178.4.67.6178.4.67.76
98178.4.67.8/29178.4.67.9 to 178.4.67.14178.4.67.156
99178.4.67.16/29178.4.67.17 to 178.4.67.22178.4.67.236
100178.4.67.24/29178.4.67.25 to 178.4.67.30178.4.67.316
101178.4.67.32/29178.4.67.33 to 178.4.67.38178.4.67.396
102178.4.67.40/29178.4.67.41 to 178.4.67.46178.4.67.476
103178.4.67.48/29178.4.67.49 to 178.4.67.54178.4.67.556
104178.4.67.56/29178.4.67.57 to 178.4.67.62178.4.67.636
105178.4.67.64/29178.4.67.65 to 178.4.67.70178.4.67.716
106178.4.67.72/29178.4.67.73 to 178.4.67.78178.4.67.796
107178.4.67.80/29178.4.67.81 to 178.4.67.86178.4.67.876
108178.4.67.88/29178.4.67.89 to 178.4.67.94178.4.67.956
109178.4.67.96/29178.4.67.97 to 178.4.67.102178.4.67.1036
110178.4.67.104/29178.4.67.105 to 178.4.67.110178.4.67.1116
111178.4.67.112/29178.4.67.113 to 178.4.67.118178.4.67.1196
112178.4.67.120/29178.4.67.121 to 178.4.67.126178.4.67.1276
113178.4.67.128/29178.4.67.129 to 178.4.67.134178.4.67.1356
114178.4.67.136/29178.4.67.137 to 178.4.67.142178.4.67.1436
115178.4.67.144/29178.4.67.145 to 178.4.67.150178.4.67.1516
116178.4.67.152/29178.4.67.153 to 178.4.67.158178.4.67.1596
117178.4.67.160/29178.4.67.161 to 178.4.67.166178.4.67.1676
118178.4.67.168/29178.4.67.169 to 178.4.67.174178.4.67.1756
119178.4.67.176/29178.4.67.177 to 178.4.67.182178.4.67.1836
120178.4.67.184/29178.4.67.185 to 178.4.67.190178.4.67.1916
121178.4.67.192/29178.4.67.193 to 178.4.67.198178.4.67.1996
122178.4.67.200/29178.4.67.201 to 178.4.67.206178.4.67.2076
123178.4.67.208/29178.4.67.209 to 178.4.67.214178.4.67.2156
124178.4.67.216/29178.4.67.217 to 178.4.67.222178.4.67.2236
125178.4.67.224/29178.4.67.225 to 178.4.67.230178.4.67.2316
126178.4.67.232/29178.4.67.233 to 178.4.67.238178.4.67.2396
127178.4.67.240/29178.4.67.241 to 178.4.67.246178.4.67.2476
128178.4.67.248/29178.4.67.249 to 178.4.67.254178.4.67.2556
129178.4.68.0/29178.4.68.1 to 178.4.68.6178.4.68.76
130178.4.68.8/29178.4.68.9 to 178.4.68.14178.4.68.156
131178.4.68.16/29178.4.68.17 to 178.4.68.22178.4.68.236
132178.4.68.24/29178.4.68.25 to 178.4.68.30178.4.68.316
133178.4.68.32/29178.4.68.33 to 178.4.68.38178.4.68.396
134178.4.68.40/29178.4.68.41 to 178.4.68.46178.4.68.476
135178.4.68.48/29178.4.68.49 to 178.4.68.54178.4.68.556
136178.4.68.56/29178.4.68.57 to 178.4.68.62178.4.68.636
137178.4.68.64/29178.4.68.65 to 178.4.68.70178.4.68.716
138178.4.68.72/29178.4.68.73 to 178.4.68.78178.4.68.796
139178.4.68.80/29178.4.68.81 to 178.4.68.86178.4.68.876
140178.4.68.88/29178.4.68.89 to 178.4.68.94178.4.68.956
141178.4.68.96/29178.4.68.97 to 178.4.68.102178.4.68.1036
142178.4.68.104/29178.4.68.105 to 178.4.68.110178.4.68.1116
143178.4.68.112/29178.4.68.113 to 178.4.68.118178.4.68.1196
144178.4.68.120/29178.4.68.121 to 178.4.68.126178.4.68.1276
145178.4.68.128/29178.4.68.129 to 178.4.68.134178.4.68.1356
146178.4.68.136/29178.4.68.137 to 178.4.68.142178.4.68.1436
147178.4.68.144/29178.4.68.145 to 178.4.68.150178.4.68.1516
148178.4.68.152/29178.4.68.153 to 178.4.68.158178.4.68.1596
149178.4.68.160/29178.4.68.161 to 178.4.68.166178.4.68.1676
150178.4.68.168/29178.4.68.169 to 178.4.68.174178.4.68.1756
151178.4.68.176/29178.4.68.177 to 178.4.68.182178.4.68.1836
152178.4.68.184/29178.4.68.185 to 178.4.68.190178.4.68.1916
153178.4.68.192/29178.4.68.193 to 178.4.68.198178.4.68.1996
154178.4.68.200/29178.4.68.201 to 178.4.68.206178.4.68.2076
155178.4.68.208/29178.4.68.209 to 178.4.68.214178.4.68.2156
156178.4.68.216/29178.4.68.217 to 178.4.68.222178.4.68.2236
157178.4.68.224/29178.4.68.225 to 178.4.68.230178.4.68.2316
158178.4.68.232/29178.4.68.233 to 178.4.68.238178.4.68.2396
159178.4.68.240/29178.4.68.241 to 178.4.68.246178.4.68.2476
160178.4.68.248/29178.4.68.249 to 178.4.68.254178.4.68.2556
161178.4.69.0/29178.4.69.1 to 178.4.69.6178.4.69.76
162178.4.69.8/29178.4.69.9 to 178.4.69.14178.4.69.156
163178.4.69.16/29178.4.69.17 to 178.4.69.22178.4.69.236
164178.4.69.24/29178.4.69.25 to 178.4.69.30178.4.69.316
165178.4.69.32/29178.4.69.33 to 178.4.69.38178.4.69.396
166178.4.69.40/29178.4.69.41 to 178.4.69.46178.4.69.476
167178.4.69.48/29178.4.69.49 to 178.4.69.54178.4.69.556
168178.4.69.56/29178.4.69.57 to 178.4.69.62178.4.69.636
169178.4.69.64/29178.4.69.65 to 178.4.69.70178.4.69.716
170178.4.69.72/29178.4.69.73 to 178.4.69.78178.4.69.796
171178.4.69.80/29178.4.69.81 to 178.4.69.86178.4.69.876
172178.4.69.88/29178.4.69.89 to 178.4.69.94178.4.69.956
173178.4.69.96/29178.4.69.97 to 178.4.69.102178.4.69.1036
174178.4.69.104/29178.4.69.105 to 178.4.69.110178.4.69.1116
175178.4.69.112/29178.4.69.113 to 178.4.69.118178.4.69.1196
176178.4.69.120/29178.4.69.121 to 178.4.69.126178.4.69.1276
177178.4.69.128/29178.4.69.129 to 178.4.69.134178.4.69.1356
178178.4.69.136/29178.4.69.137 to 178.4.69.142178.4.69.1436
179178.4.69.144/29178.4.69.145 to 178.4.69.150178.4.69.1516
180178.4.69.152/29178.4.69.153 to 178.4.69.158178.4.69.1596
181178.4.69.160/29178.4.69.161 to 178.4.69.166178.4.69.1676
182178.4.69.168/29178.4.69.169 to 178.4.69.174178.4.69.1756
183178.4.69.176/29178.4.69.177 to 178.4.69.182178.4.69.1836
184178.4.69.184/29178.4.69.185 to 178.4.69.190178.4.69.1916
185178.4.69.192/29178.4.69.193 to 178.4.69.198178.4.69.1996
186178.4.69.200/29178.4.69.201 to 178.4.69.206178.4.69.2076
187178.4.69.208/29178.4.69.209 to 178.4.69.214178.4.69.2156
188178.4.69.216/29178.4.69.217 to 178.4.69.222178.4.69.2236
189178.4.69.224/29178.4.69.225 to 178.4.69.230178.4.69.2316
190178.4.69.232/29178.4.69.233 to 178.4.69.238178.4.69.2396
191178.4.69.240/29178.4.69.241 to 178.4.69.246178.4.69.2476
192178.4.69.248/29178.4.69.249 to 178.4.69.254178.4.69.2556
193178.4.70.0/29178.4.70.1 to 178.4.70.6178.4.70.76
194178.4.70.8/29178.4.70.9 to 178.4.70.14178.4.70.156
195178.4.70.16/29178.4.70.17 to 178.4.70.22178.4.70.236
196178.4.70.24/29178.4.70.25 to 178.4.70.30178.4.70.316
197178.4.70.32/29178.4.70.33 to 178.4.70.38178.4.70.396
198178.4.70.40/29178.4.70.41 to 178.4.70.46178.4.70.476
199178.4.70.48/29178.4.70.49 to 178.4.70.54178.4.70.556
200178.4.70.56/29178.4.70.57 to 178.4.70.62178.4.70.636
201178.4.70.64/29178.4.70.65 to 178.4.70.70178.4.70.716
202178.4.70.72/29178.4.70.73 to 178.4.70.78178.4.70.796
203178.4.70.80/29178.4.70.81 to 178.4.70.86178.4.70.876
204178.4.70.88/29178.4.70.89 to 178.4.70.94178.4.70.956
205178.4.70.96/29178.4.70.97 to 178.4.70.102178.4.70.1036
206178.4.70.104/29178.4.70.105 to 178.4.70.110178.4.70.1116
207178.4.70.112/29178.4.70.113 to 178.4.70.118178.4.70.1196
208178.4.70.120/29178.4.70.121 to 178.4.70.126178.4.70.1276
209178.4.70.128/29178.4.70.129 to 178.4.70.134178.4.70.1356
210178.4.70.136/29178.4.70.137 to 178.4.70.142178.4.70.1436
211178.4.70.144/29178.4.70.145 to 178.4.70.150178.4.70.1516
212178.4.70.152/29178.4.70.153 to 178.4.70.158178.4.70.1596
213178.4.70.160/29178.4.70.161 to 178.4.70.166178.4.70.1676
214178.4.70.168/29178.4.70.169 to 178.4.70.174178.4.70.1756
215178.4.70.176/29178.4.70.177 to 178.4.70.182178.4.70.1836
216178.4.70.184/29178.4.70.185 to 178.4.70.190178.4.70.1916
217178.4.70.192/29178.4.70.193 to 178.4.70.198178.4.70.1996
218178.4.70.200/29178.4.70.201 to 178.4.70.206178.4.70.2076
219178.4.70.208/29178.4.70.209 to 178.4.70.214178.4.70.2156
220178.4.70.216/29178.4.70.217 to 178.4.70.222178.4.70.2236
221178.4.70.224/29178.4.70.225 to 178.4.70.230178.4.70.2316
222178.4.70.232/29178.4.70.233 to 178.4.70.238178.4.70.2396
223178.4.70.240/29178.4.70.241 to 178.4.70.246178.4.70.2476
224178.4.70.248/29178.4.70.249 to 178.4.70.254178.4.70.2556
225178.4.71.0/29178.4.71.1 to 178.4.71.6178.4.71.76
226178.4.71.8/29178.4.71.9 to 178.4.71.14178.4.71.156
227178.4.71.16/29178.4.71.17 to 178.4.71.22178.4.71.236
228178.4.71.24/29178.4.71.25 to 178.4.71.30178.4.71.316
229178.4.71.32/29178.4.71.33 to 178.4.71.38178.4.71.396
230178.4.71.40/29178.4.71.41 to 178.4.71.46178.4.71.476
231178.4.71.48/29178.4.71.49 to 178.4.71.54178.4.71.556
232178.4.71.56/29178.4.71.57 to 178.4.71.62178.4.71.636
233178.4.71.64/29178.4.71.65 to 178.4.71.70178.4.71.716
234178.4.71.72/29178.4.71.73 to 178.4.71.78178.4.71.796
235178.4.71.80/29178.4.71.81 to 178.4.71.86178.4.71.876
236178.4.71.88/29178.4.71.89 to 178.4.71.94178.4.71.956
237178.4.71.96/29178.4.71.97 to 178.4.71.102178.4.71.1036
238178.4.71.104/29178.4.71.105 to 178.4.71.110178.4.71.1116
239178.4.71.112/29178.4.71.113 to 178.4.71.118178.4.71.1196
240178.4.71.120/29178.4.71.121 to 178.4.71.126178.4.71.1276
241178.4.71.128/29178.4.71.129 to 178.4.71.134178.4.71.1356
242178.4.71.136/29178.4.71.137 to 178.4.71.142178.4.71.1436
243178.4.71.144/29178.4.71.145 to 178.4.71.150178.4.71.1516
244178.4.71.152/29178.4.71.153 to 178.4.71.158178.4.71.1596
245178.4.71.160/29178.4.71.161 to 178.4.71.166178.4.71.1676
246178.4.71.168/29178.4.71.169 to 178.4.71.174178.4.71.1756
247178.4.71.176/29178.4.71.177 to 178.4.71.182178.4.71.1836
248178.4.71.184/29178.4.71.185 to 178.4.71.190178.4.71.1916
249178.4.71.192/29178.4.71.193 to 178.4.71.198178.4.71.1996
250178.4.71.200/29178.4.71.201 to 178.4.71.206178.4.71.2076
251178.4.71.208/29178.4.71.209 to 178.4.71.214178.4.71.2156
252178.4.71.216/29178.4.71.217 to 178.4.71.222178.4.71.2236
253178.4.71.224/29178.4.71.225 to 178.4.71.230178.4.71.2316
254178.4.71.232/29178.4.71.233 to 178.4.71.238178.4.71.2396
255178.4.71.240/29178.4.71.241 to 178.4.71.246178.4.71.2476
256178.4.71.248/29178.4.71.249 to 178.4.71.254178.4.71.2556

IPv4 CIDR reference (/0 to /32)

IPv4 prefix lengths
PrefixSubnet maskWildcardAddressesUsable hostsSizeTypical use
/00.0.0.0255.255.255.2554,294,967,2964,294,967,29416,777,216 × /24
/1128.0.0.0127.255.255.2552,147,483,6482,147,483,6468,388,608 × /24
/2192.0.0.063.255.255.2551,073,741,8241,073,741,8224,194,304 × /24
/3224.0.0.031.255.255.255536,870,912536,870,9102,097,152 × /24
/4240.0.0.015.255.255.255268,435,456268,435,4541,048,576 × /24
/5248.0.0.07.255.255.255134,217,728134,217,726524,288 × /24
/6252.0.0.03.255.255.25567,108,86467,108,862262,144 × /24
/7254.0.0.01.255.255.25533,554,43233,554,430131,072 × /24
/8255.0.0.00.255.255.25516,777,21616,777,21465,536 × /24Old class A; 10.0.0.0/8
/9255.128.0.00.127.255.2558,388,6088,388,60632,768 × /24
/10255.192.0.00.63.255.2554,194,3044,194,30216,384 × /24
/11255.224.0.00.31.255.2552,097,1522,097,1508,192 × /24
/12255.240.0.00.15.255.2551,048,5761,048,5744,096 × /24172.16.0.0/12
/13255.248.0.00.7.255.255524,288524,2862,048 × /24
/14255.252.0.00.3.255.255262,144262,1421,024 × /24
/15255.254.0.00.1.255.255131,072131,070512 × /24
/16255.255.0.00.0.255.25565,53665,534256 × /24Old class B; 192.168.0.0/16
/17255.255.128.00.0.127.25532,76832,766128 × /24
/18255.255.192.00.0.63.25516,38416,38264 × /24
/19255.255.224.00.0.31.2558,1928,19032 × /24
/20255.255.240.00.0.15.2554,0964,09416 × /24
/21255.255.248.00.0.7.2552,0482,0468 × /24
/22255.255.252.00.0.3.2551,0241,0224 × /24Large office or guest Wi-Fi (1,022 hosts)
/23255.255.254.00.0.1.2555125102 × /24Larger office LAN (510 hosts)
/24255.255.255.00.0.0.2552562541 × /24Typical office LAN (old class C)
/25255.255.255.1280.0.0.1271281261/2 of a /24Smaller LAN or VLAN
/26255.255.255.1920.0.0.6364621/4 of a /24Smaller LAN or VLAN
/27255.255.255.2240.0.0.3132301/8 of a /24Small VLAN, phones, cameras
/28255.255.255.2400.0.0.1516141/16 of a /24Small VLAN, phones, cameras
/29255.255.255.2480.0.0.7861/32 of a /24Small fixed public block (5 usable)
/30255.255.255.2520.0.0.3421/64 of a /24Point-to-point (old style)
/31255.255.255.2540.0.0.1221/128 of a /24Point-to-point link (RFC 3021)
/32255.255.255.2550.0.0.0111/256 of a /24One host

IPv6 prefix reference

IPv6 prefix lengths
PrefixAddresses/64 LANs/48 sitesNibbleTypical use
/342,535,295,865,117,307,932,921,825,928,971,026,432 (2^125)2,305,843,009,213,693,95235,184,372,088,832NoAll global unicast (2000::/3)
/165,192,296,858,534,827,628,530,496,329,220,096 (2^112)281,474,976,710,6564,294,967,296Yes
/20324,518,553,658,426,726,783,156,020,576,256 (2^108)17,592,186,044,416268,435,456YesLarge provider allocation (RIPE minimum for some)
/29633,825,300,114,114,700,748,351,602,688 (2^99)34,359,738,368524,288NoRIPE allocation to a provider (often)
/3279,228,162,514,264,337,593,543,950,336 (2^96)4,294,967,29665,536YesProvider allocation (RIPE default)
/364,951,760,157,141,521,099,596,496,896 (2^92)268,435,4564,096Yes
/40309,485,009,821,345,068,724,781,056 (2^88)16,777,216256Yes
/4419,342,813,113,834,066,795,298,816 (2^84)1,048,57616Yes
/481,208,925,819,614,629,174,706,176 (2^80)65,5361YesOne site or organisation (RIPE PI / assignment)
/5275,557,863,725,914,323,419,136 (2^76)4,096Yes
/564,722,366,482,869,645,213,696 (2^72)256YesSmall site or home (common provider assignment)
/60295,147,905,179,352,825,856 (2^68)16YesSome home broadband (16 LANs)
/6418,446,744,073,709,551,616 (2^64)1YesOne LAN or VLAN (needed for SLAAC)
/7272,057,594,037,927,936 (2^56)1/256 of a /64Yes
/80281,474,976,710,656 (2^48)1/65,536 of a /64Yes
/964,294,967,2961/4,294,967,296 of a /64YesEmbeds an IPv4 address (NAT64)
/11265,5361/281,474,976,710,656 of a /64Yes
/1202561/72,057,594,037,927,936 of a /64Yes
/124161/1,152,921,504,606,846,976 of a /64Yes
/12641/4,611,686,018,427,387,904 of a /64No
/12721/9,223,372,036,854,775,808 of a /64NoPoint-to-point link (RFC 6164)
/12811/18,446,744,073,709,551,616 of a /64YesOne host or loopback

Private and special ranges

IPv4

Special-purpose ranges
RangeNameWhat it is
255.255.255.255/32Limited broadcastEvery host on the local network
0.0.0.0/8This networkNot routed; 0.0.0.0 means "any address" in settings
10.0.0.0/8Private (RFC 1918)Office and home networks; not routed on the internet
100.64.0.0/10Shared address space (CGNAT)Used by providers behind carrier-grade NAT (RFC 6598)
127.0.0.0/8LoopbackThis computer
169.254.0.0/16Link-local (APIPA)Self-assigned when no DHCP server answers
172.16.0.0/12Private (RFC 1918)Office and home networks; not routed on the internet
192.0.0.0/24IETF protocol assignmentsSpecial uses such as DS-Lite
192.0.2.0/24Documentation (TEST-NET-1)For examples; never used on a network
192.88.99.0/246to4 relay (deprecated)Formerly anycast for 6to4
192.168.0.0/16Private (RFC 1918)Office and home networks; not routed on the internet
198.18.0.0/15BenchmarkingNetwork equipment testing (RFC 2544)
198.51.100.0/24Documentation (TEST-NET-2)For examples; never used on a network
203.0.113.0/24Documentation (TEST-NET-3)For examples; never used on a network
224.0.0.0/4MulticastOne-to-many traffic, such as IPTV and routing protocols
240.0.0.0/4ReservedFuture use; not usable on most systems

IPv6

Special-purpose ranges
RangeNameWhat it is
::/128UnspecifiedNo address; :: means "any address" in settings
::1/128LoopbackThis computer
::ffff:0:0/96IPv4-mappedAn IPv4 address written as IPv6
64:ff9b::/96NAT64IPv4 addresses reached through a NAT64 gateway
100::/64Discard onlyTraffic sent here is dropped (RFC 6666)
2001:db8::/32DocumentationFor examples; never used on a network
2001::/32TeredoIPv6 tunnelled over IPv4 UDP
2002::/166to4IPv6 tunnelled over IPv4 (largely retired)
3fff::/20DocumentationFor examples (RFC 9637)
fc00::/7Unique local (ULA)Private IPv6, like RFC 1918; usually fd00::/8
fe80::/10Link-localEvery IPv6 interface has one; not routed
ff00::/8MulticastOne-to-many traffic; replaces broadcast
2000::/3Global unicastPublic internet addresses

About this tool

A network is written as an address and a prefix length, such as 192.168.1.0/24: the first 24 bits name the network and the rest number the devices on it. The calculator works out where the network starts and ends, how many devices it holds, its subnet and wildcard masks, and the reverse DNS zone to ask your provider for.

It also splits a network into equal smaller ones (one per VLAN or site), turns a range of addresses into the fewest CIDR blocks for a firewall rule, and lists every IPv4 prefix length and the common IPv6 ones in reference tables.

Common questions

Why are two addresses lost in every IPv4 subnet?

The first address names the network and the last is the broadcast address, so a /24 has 256 addresses but 254 for devices. A /31 (a link between two routers) and a /32 (one host) are the exceptions.

What size of IPv6 network should a LAN use?

Always /64. Devices pick their own address within it (SLAAC), which needs the full 64 bits. A site usually gets a /48 or /56 from its provider, which holds 65,536 or 256 LANs.

What is a wildcard mask?

The subnet mask turned inside out: 255.255.255.0 becomes 0.0.0.255. Cisco access lists and OSPF use it to say which bits must match.

Which ranges can I use inside an office?

IPv4: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. IPv6: unique local addresses from fd00::/8, though most networks use the public prefix from their provider.